﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
using System.IO;

namespace Utilities
{
    /// <summary>
    /// 安全加密帮助类
    /// </summary>
    public class SecurityHelper
    {
        /// <summary> 
        /// DES加解密工具类
        /// </summary> 
        public class DESEncrypt
        {
            //默认密钥向量
            private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
            /// <summary>
            /// DES加密字符串
            /// </summary>
            /// <param name="encryptString">待加密的字符串</param>
            /// <param name="encryptKey">加密密钥,要求为8位</param>
            /// <returns>加密成功返回加密后的字符串,失败返回源串</returns>
            public static string Encode(string encryptString, string encryptKey)
            {                
                encryptKey = StringHelper.GetSubString(encryptKey, 8, "");
                encryptKey = encryptKey.PadRight(8, ' ');
                byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));
                byte[] rgbIV = Keys;
                byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
                DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Convert.ToBase64String(mStream.ToArray());

            }
            /// <summary>
            /// DES解密字符串
            /// </summary>
            /// <param name="decryptString">待解密的字符串</param>
            /// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>
            /// <returns>解密成功返回解密后的字符串,失败返源串</returns>
            public static string Decode(string decryptString, string decryptKey)
            {
                try
                {
                    decryptKey = StringHelper.GetSubString(decryptKey, 8, "");
                    decryptKey = decryptKey.PadRight(8, ' ');
                    byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);
                    byte[] rgbIV = Keys;
                    byte[] inputByteArray = Convert.FromBase64String(decryptString);
                    DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();

                    MemoryStream mStream = new MemoryStream();
                    CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                    cStream.Write(inputByteArray, 0, inputByteArray.Length);
                    cStream.FlushFinalBlock();
                    return Encoding.UTF8.GetString(mStream.ToArray());
                }
                catch
                {
                    return null;
                }
            }
        }
        /// <summary> 
        /// AES加解密工具类
        /// </summary> 
        public class AESEncrypt
        {
            private static byte[] Keys = { 0x41, 0x72, 0x65, 0x79, 0x6F, 0x75, 0x6D, 0x79, 0x53, 0x6E, 0x6F, 0x77, 0x6D, 0x61, 0x6E, 0x3F };
            /// <summary>
            /// 加密指定字符串
            /// </summary>
            /// <param name="encryptString">要加密的字符串</param>
            /// <param name="encryptKey">密钥</param>
            /// <returns>加密后的字符串</returns>
            public static string Encode(string encryptString, string encryptKey)
            {
                encryptKey = StringHelper.GetSubString(encryptKey, 32, "");
                encryptKey = encryptKey.PadRight(32, ' ');

                RijndaelManaged rijndaelProvider = new RijndaelManaged();
                rijndaelProvider.Key = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 32));
                rijndaelProvider.IV = Keys;
                ICryptoTransform rijndaelEncrypt = rijndaelProvider.CreateEncryptor();

                byte[] inputData = Encoding.UTF8.GetBytes(encryptString);
                byte[] encryptedData = rijndaelEncrypt.TransformFinalBlock(inputData, 0, inputData.Length);

                return Convert.ToBase64String(encryptedData);
            }
            /// <summary>
            /// 解密指定的字符串
            /// </summary>
            /// <param name="decryptString">调用Encode加密方法加密过的字符串</param>
            /// <param name="decryptKey">密钥</param>
            /// <returns>解密后的字符串</returns>
            public static string Decode(string decryptString, string decryptKey)
            {
                try
                {
                    decryptKey = StringHelper.GetSubString(decryptKey, 32, "");
                    decryptKey = decryptKey.PadRight(32, ' ');

                    RijndaelManaged rijndaelProvider = new RijndaelManaged();
                    rijndaelProvider.Key = Encoding.UTF8.GetBytes(decryptKey);
                    rijndaelProvider.IV = Keys;
                    ICryptoTransform rijndaelDecrypt = rijndaelProvider.CreateDecryptor();

                    byte[] inputData = Convert.FromBase64String(decryptString);
                    byte[] decryptedData = rijndaelDecrypt.TransformFinalBlock(inputData, 0, inputData.Length);

                    return Encoding.UTF8.GetString(decryptedData);
                }
                catch
                {
                    return "";
                }

            }
        }
        /// <summary>
        /// 
        /// </summary>
        public class MD5
        {
            /// <summary>
            /// 加密字符串
            /// </summary>
            /// <param name="sourceString"></param>
            /// <returns></returns>
            public static string Encrypt(string sourceString)
            {
                if (string.IsNullOrEmpty(sourceString))
                {
                    throw new Exception("<Encrypt Error>sourceString is null");
                }

                var md5 = new MD5CryptoServiceProvider();
                var buffer = md5.ComputeHash(Encoding.UTF8.GetBytes(sourceString));
                var sb = new StringBuilder(32);
                foreach (var t in buffer)
                {
                    sb.Append(t.ToString("X2"));
                }

                md5.Dispose();
                return sb.ToString();
            }

            /// <summary>
            /// 16位MD5加密
            /// </summary>
            /// <param name="sourceString"></param>
            /// <returns></returns>
            public static string Encrypt16(string sourceString)
            {
                var md5 = new MD5CryptoServiceProvider();
                string t2 = BitConverter.ToString(md5.ComputeHash(Encoding.Default.GetBytes(sourceString)), 4, 8);
                t2 = t2.Replace("-", "");
                return t2;
            }
        } 
        
    }
}
